The geasy spulge left in your ass after shitting, if not wiped properly. It can sometimes occur even after a thorough wiping because occasionally your rectum may seep. Warm and humid weather may also intensify this harsh reality.
After taking a growler, I realized i had a bad case of monkey butt on the par three 5th. There was no outhouse around!
by pis2114 May 27, 2006
A chafe recieved between the upper thighs and asscrack brought about by sweaty activities such as walking back and forth or working out of doors. Produces a Baboon-like rash on the buttocks.
"Man, I got a serious case of monkeybutt bartending tonight!" or "Landscaping gave the rudest monkeybutt yesterday!"
by Mick September 21, 2003